Liberal versus restrictive transfusion strategies in patients with acute brain injury: a systematic review and meta-analysis of randomized controlled trials

TL;DR

This study compares liberal and restrictive blood transfusion strategies in patients with acute brain injury and anemia, finding no significant difference in neurological outcomes but a reduction in sepsis with the liberal approach.

Contribution

The study provides a meta-analysis of randomized trials to evaluate transfusion strategies in acute brain injury patients.

Findings

No significant difference in neurological outcomes between liberal and restrictive transfusion strategies.

Liberal transfusion reduced sepsis or septic shock but increased red blood cell transfusions.

No impact on mortality or thrombotic events with either strategy.

Abstract

Anemia has been observed in up to 46% of individuals with acute brain injury. Blood transfusions are commonly performed to raise hemoglobin levels, so we aimed to compare the restrictive and liberal blood transfusion strategies in acute brain injury patients.

A systematic search was conducted on Web of Science, Embase, Scopus, Cochrane, and Medline/PubMed up to February 10, 2025. Continuous data were combined using mean differences (MD), and dichotomous outcomes were synthesized using risk ratios (RR); both were detailed with a 95% confidence interval (CI), applying R software (version 4.3). This study was registered and published with PROSPERO (ID CRD42025630392).

The analysis incorporated six randomized controlled trials involving 2599 participants. There were no substantial variations between the liberal and restrictive transfusion groups in unfavorable neurological outcomes (RR: 0.90 [95% CI: 0.79–1.03]; P = 0.13), favorable neurological outcomes (RR: 1.16 [95% CI: 1.00–1.35]; P = 0.05), hospital length of stay (MD: −0.66 [95% CI: −2.48–1.16]; P = 0.48), or intensive care unit length of stay (MD: 0.15 [95% CI: −0.68–0.99]; P = 0.72). However, the liberal transfusion strategy was accompanied with an increased number of red cell units transfused (MD: 2.28, 95% CI: [1.75–2.80]; P < 0.01) and reduced sepsis or septic shock compared to the restrictive strategy (RR: 0.73 [95% CI: 0.56–0.96]; P = 0.02).

The liberal strategy of blood transfusion for patients with acute brain injury and anemia did not impact neurological outcomes. It reduced the incidence of sepsis or septic shock, but this came with an increase in the number of red blood cells transfused without affecting overall mortality or thrombotic events.

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